冲击波作用下水下结构载荷计算方法

LOADING EVALUATION METHOD OF SUBMERGED STRUCTURE SUBJECTED TO SHOCK WAVE

针对冲击波激励下水下结构与无限声学水域的流固耦合问题,建立了冲击波及无限水域作用在结构上的载荷计算方法。该方法采用场分离技术将水下结构载荷分解为冲击波压力及散射波压力,而散射波压力又分解成反射波压力和辐射波压力。基于比例边界有限元法,建立反射波压力计算方法,而辐射波压力由有限元商业软件的声固耦合技术确定。该文利用该方法在商业有限元软件中分析了一经典算例,分析结果表明该方法能有效模拟冲击波作用下水下结构载荷及其响应,避免了冲击波在无限流体中传播的有限元分析,降低了分析规模。

Aiming for fluid-structure interaction problems between a submerged structure under shock wave excitations and infinite acoustic fluid, a method is proposed to evaluate loadings acting on submerged structures caused by shock waves and infinite acoustic fluid. Utilizing field separation technique, the proposed method decomposes these loadings into two components, shock wave pressure and scattered wave pressure. The scatted wave pressure is further decomposed into two parts, reflection wave pressure and radiation wave pressure. Based on the scaled boundary finite element method(SBFEM), a method is proposed to evaluate reflection wave pressure, while radiation wave pressure is determined by an acoustic-structure coupling technique used in a commercial finite element software. A classic benchmark example is analyzed through the proposed method in the commercial finite element software ‘Ansys'. The analysis results show that the proposed method can efficiently evaluate the loadings and structural responses of a submerged structure under shock wave excitations, so as to avoid implementing the finite element analysis of shock wave propagation in infinite fluid which decreases analysis scale.